The overall, long-term objective of this research is to use tissue engineering strategies to generate de novo adipose tissue for utilization as a platform technology in clinical, diagnostic, and research applications that ultimately impact patient quality of life and outcomes. Unlike many organ and tissue applications in the field of tissue engineering, cell sourcing is not a major constraint for adipose tissue since precursor cells, preadipocytes, are readily present in the adult and can be isolated and expanded. We and others have previously demonstrated feasibility for adipose tissue engineering using PAs in vitro and in vivo for oncologic reconstructive surgery applications. However, there remains a tremendous and critical gap in providing clinically relevant volumes of adipose tissue. Namely, the furtherance of hypothesis-driven studies and clinical translation requires the development of an ex vivo culture system capable of generating adipose tissue using autologous cells and sophisticated scaffolds. We hypothesize that de novo adipose tissue can be generated with correct structure and function and maintained in a low shear, perfused bioreactor. To address this hypothesis, the following specific aims are proposed for a two-year period: 1. Determine the requisite system, cellular, and molecular requirements that support the generation of adipose tissue within a three dimensional, perfused rotating cell culture system (RCCS), and 2. Correlate the histological architecture and function of the RCCS-grown adipose tissue to that of endogenous adipose tissue using a comprehensive battery of assays and metrics integrated over multiple levels of analysis. The generation of adipose tissue engenders several unique design constraints that are not realized with the majority of mammalian tissues, providing a significant research challenge for three-dimensional tissue production. Successful completion of this proof-of-principle study will provide critical enabling technology that permits the translation of engineered adipose tissue to widely applicable clinical, diagnostic, and research applications.